U.S. Pat. No. 4,213,458 discloses an ostomy appliance in which a microporous patch is secured to a thermoplastic ostomy pouch by means of a flexible, non-porous, intermediate attachment ring. The attachment ring functions to distribute forces that might otherwise tear the relatively fragile microporous adhesive patch when the appliance is in use. While it might be thought that tearing problems could be reduced by utilizing microporous fabric of greater thickness, the heat transmission characteristics of microporous material of greater thickness tend to interfere with effective heat sealing of such material to the thermoplastic attaching ring. Less fragile microporous materials might be used, such as those containing reinforcing films or fibers, but then the advantages of greater strength tend to be offset by lower vapor transmission rates. Unless the microporous material has transmission rates for water vapor and other gases that exceed those of a patient's skin, moisture is likely to accummulate between the adhesive patch and the skin resulting in maceration, patient discomfort, and a reduction in the strength of adhesive attachment.
The security of such adhesive attachment, as well as patient comfort and skin condition in the peristomal region, may also be adversely affected by the fluids discharged through the patient's stoma. Protective skin barrier rings formed of karaya or any of a number of other compositions (U.S. Pat. Nos. 4,477,325 and 4,496,357) are therefore commonly used. Such skin barrier materials are soft, pliable, and of high surface tack (both dry and wet), thereby providing semi-solid sealant barriers to protect the skin against the excoriating effects of the stomal effluent. However, such barrier materials characteristically absorb liquid with the result that both liquids and gases may gradually migrate into the microporous patches. Also, effluent coming into contact with the inner edges of a microporous patch may wick outwardly through the patch, thereby causing effluent to reach those areas of the skin contacted by the adhesive patch. A microporous patch may therefore become a pathway for radially outward migration of fluids and gases.
Where a patch or faceplate (whether microporous or not) is secured to a thermoplastic pouch by a heat-sealing operation, a further complication arises, as disclosed in published European patent application 81303312.3 (publication No. 0045587). In the production of an ostomy pouch, the starting material is usually in the form of two webs of thermoplastic material that are advanced stepwise through three manufacturing stations. At the first station, one of the webs is punched to form what will ultimately be the stomal opening in the wall of the pouch. The adhesive patch or faceplate is then heat sealed to the web about that opening, and the two webs are finally brought together and united along their margins by a further heat-sealing operation. Since the margins of the pouch cannot be heat sealed through the faceplate, the result is a construction in which the margins of the faceplate must generally fall within the margins of the pouch. This means that for production reasons the pouch must be made larger than would otherwise be necessary or, conversely, that the faceplate must be smaller than needed or desired. While production techniques are known for overcoming this problem so as to produce an appliance having a faceplate of relatively large size, such procedures tend to be complicated (as indicated in the published application) and therefore expensive.
Other patents illustrative of the state of the art are U.S. Pat. Nos. 3,898,990 and 4,203,445.
A main aspect of this invention therefore lies in providing an ostomy appliance and method which overcome the aforementioned defects and disadvantages of prior constructions and manufacturing procedures. More specifically, the invention involves an improved construction in which the appliance is, or may be, of relatively low profile, has a skin barrier ring of extended life occasioned by the greater thickness of the barrier ring permitted by such construction, and in which the microporous patch is isolated from direct fluid contact even along its edges. The invention allows the use of microporous material of increased thickness (otherwise not feasible because of poor heat transmission characteristics) which, at the same time, has high water vapor transmission properties. The components of the appliance are arranged and constructed so that they are non-wicking in use, present only relatively soft, non-irritating materials for direct contact with the stoma, and permit the use of a rotatable belt-attachment ring for convenient adjustment of the pouch into generally vertical condition for more effective collection of effluent. In addition, the invention results in a construction which permits the use of a faceplate of any desired size regardless of pouch dimensions. In a preferred embodiment, the porous patch of the faceplate has at least a portion of its periphery extending outwardly beyond the peripheral limits of the pouch, yet such a construction is readily manufactured without the complex procedures disclosed in the prior art. Conversely, the present invention permits a reduction of those pouch dimensions that have been required in the past not because they were believed useful for pouch operation but because they were deemed necessary for ease and economy of production.
In brief, the ostomy appliance of this invention comprises an ostomy pouch equipped with a faceplate for adhesive attachment to a patient. The faceplate includes three main components: a skin barrier ring, a microporous patch, and a connecting ring that joins together the skin barrier ring, microporous patch, and pouch. The microporous patch has an enlarged opening that receives and circumscribes the skin barrier ring and, in the preferred embodiment, the distal or outwardly-facing surfaces of both the microporous patch and the skin barrier ring lie along the same plane.
The connecting ring is formed of a thin layer of soft, flexible, liquid and gas impermeable, close-cell, thermoplastic foam. The connecting ring is heat sealed to the pouch about the pouch's stoma opening and, in production, such components are so joined to form a first subassembly. The other subassembly comprises the microporous patch and skin barrier rin supported with their distal surfaces in concentric coplanar relation by means of a disposable supporting cover or cup. The two subassemblies are brought together and adhesively joined with the foam connecting ring being adhesively secured to the distal surfaces of the skin barrier ring and a portion of the microporous patch surrounding the barrier ring. Since the attachment is an adhesive one, the microporous patch may be of any desired outline and size and the upper portion of the pouch may be relatively narrow, thereby avoiding the excessive dimensions commonly found in the upper portions of conventional ostomy pouches.
Other features, advantages, and objects of the invention will become apparent from the specification and drawings.